Pulse-jet engines of the valveless type



Nov. 28, 1967 R- MALRQUX PULSE-JET ENGINES OF THE VALVELESS TYPE 2 Sheets-Sheet 2 Filed Oct. 6, 1965 Own Q m NT L6 val United States Patent 3,354,650 PULSE-JET ENGINES OF THE VALVELESS TYPE Rene Malroux, Villeneuve-le-Roi, France, assignor to Pulse Jet Corporation, Chicago, Ill., a corporation of Delaware Filed Oct. 6, 1965, Ser. No. 493,324

2 Claims. (Cl. 60-249) ABSTRACT OF THE DISCLOSURE A valveless pulse-jet engine comprising an elongated longitudinally extending tubular first section defining therein a primary combustion chamber, a cap connected to the front end of the first section and closing the adjacent front end of the primary combustion chamber to the atmosphere, an elongated longitudinally extending and rearwardly converging tubular second section defining therein a secondary combustion chamber, the rear end of the first section being connected to the front end of the second section with the rear end of the primary combustion chamber opening into the adjacent front end of the secondary combustion chamber, an elongated longitudinally extending tubular third section defining an exhaust passage therethrough, the rear end of the second section being connected to the front end of the third section with the rear end of the secondary combustion chamber opening into the front end of the exhaust passage, the rear end of the third section being open, whereby the rear end of the exhaust passage constitutes an exhaust gas nozzle communicating with the atmosphere, the second section having a length that is about /2 of that of the first section and that is about A; of that of the third section, an elongated longitudinally extending tubular fourth section defining an inlet passage therethrough, one end of the fourth section being connected to the front portion of the second section with the adjacent one end of the inlet passage opening into the front portion of the secondary combustion chamber, the other end of the fourth section being open, whereby the adjacent other end of the inlet passage constitutes an air inlet nozzle communicating with the atmosphere, means for injecting fuel in finely divided form forwardly through the front end of the secondary combustion chamber and into the rear end of the primary combustion chamber and directed toward the front end thereof, and means for igniting the combustible mixture of fuel and air in the primary combustion chamber.

It is a general object of the invention to provide a pulse-jet engine of the valveless type that is of compact and economical construction and having a greater thrust per unit weight and per unit volume than prior such engines of this type.

Another object of the invention is to provide a pulse-jet engine, or direct-reaction motor, subject to intermittent combustion, and provided with no moving parts, that essentially comprises an elongated longitudinally extending tubular first section defining therein a primary combustion chamber, a cap connected to the front end of the first section and closing the adjacent front end of the primary combustion chamber to the atmosphere, an elongated longitudinally extending and rearwardly converging tubular second section defining therein a secondary combustion chamber, the rear end of the first section being connected to the front end of the second section with the rear end of the primary combustion chamber opening into the adjacent front end of the secondary combustion chamber, an elongated longitudinally extending tubular third section defining an exhaust passage therethrough,

the rear end of the second section being connected to th front end of the third section with the rear end of th secondary combustion chamber opening into the front em of the exhaust passage, the rear end of the third sectior being open, whereby the rear end of the exhaust passagt constitutes an exhaust gas nozzle communicating witl the atmosphere, and an elongated longitudinally extend ing tubular fourth section defining an inlet passage therethrough, the front end of the fourth section being con nected to the front portion of the second section with the adjacent front end of the inlet passage opening into the front portion of the secondary combustion chamber, the rear end of the fourth section being open, whereby the adjacent rear end of the inlet passage constitutes an air inlet nozzle communicating with the atmosphere.

Another object of the invention is to provide a pulse-jet engine of the character described, wherein the longitudinal axes of the first and second and third sections are arranged in alignment along a common longitudinal axis, and the longitudinal axis of the fourth section is arranged in lateral off-set relation with respect to the common longitudinal axis.

A further object of the invention is to provide a pulsejet engine of the character described and comprising a plurality of the fourth sections and thus a plurality of inlet passages communicating between the front portion of the secondary combustion chamber and the atmosphere.

A further object of the invention is to provide a pulsejet engine of the character described and further comprising an elongated longitudinally extending and rearwardly diverging tubular fifth section having an aspirator passage therethrough and arranged rearwardly of the fourth section and in substantial longitudinal alignment therewith, the front end of the fifth section being open so that the adjacent front end of the aspirator passage is in direct communication with the rear end of the fourth section, and the rear end of the fifth section being open so that the adjacent rear end of the aspirator passage is in direct communication with the atmosphere.

A further object of the invention is to provide a pulsejet engine of the character described and further comprising an elongated longitudinally extending tubular sixth section defining a scoop passage therethrough, the longitudinal axis of the sixth section being disposed in lateral off-set relation with respect to the longitudinal axis of the fourth section, the front end of the sixth section being open, whereby the adjacent front end of the scoop passage constitutes a mouth communicating with the atmosphere, the rear portion of the sixth section having a return bend therein disposed adjacent to the rear end of the fourth section, the rear end of the sixth section being forwardly directed and disposed in the air inlet nozzle, the rear end of the sixth section being open, whereby the adjacent rear end of the scoop passage constitutes an air outlet nozzle communicating with the air inlet nozzle.

A still further object of the invention is to provide a pulse-jet engine of the character described, wherein the several sections thereof have advantageous relationships among the dimensions thereof.

Further features of the invention pertain to the particular arrangement of the elements of the pulse jet engine, whereby the above outlined and additional operating features thereof are attained.

The invention, both as to its organization and method of operation, together with further objects and advantages thereof, will best be understood by reference to the following specification, taken in connection with the accompanying drawings, in which:

FIGURE 1 is a longitudinal sectional View of a pulse-jet engine embodying the present invention;

FIG. 2 is an enlarged fragmentary longitudinal secmad view of a modified form of the pulse-jet engine,

shown in FIG. 1;

FIG. 3 is a reduced longitudinal sectional view of rother modified form of the pulse-jet engine, as shown FIG. 1;

FIG. 4 is an enlarged longitudinal sectional view of a )rtion of a further modified form of the pulse-jet enne, as shown in FIG. 1, this view 'being taken in the .rection of the arrows, along the line 4-4 in FIG. 5;

FIG. 5 is an enlarged plan view of the portion of the ulse-jet engine, as shown in FIG. 4;

FIG. 6 is an enlarged lateral sectional view of the poron of the pulse-jet engine, this view being taken in re direction of the arrows along the line 66 in FIG. 4; nd

FIG. 7 is an enlarged rear elevational view of the ortion of the pulse-jet engine, this view being taken in ie direction of the arrows along the line 7-7 in FIG. 4.

Referring now to FIG. 1, there is illustrated a pulseat engine, or direct reaction motor, 10 that comprises n elongated longitudinally extending tubular section 11 f substantially cylindrical configuration and defining a vrimary combustion chamber 12 therein, and a forwardly onverging substantially conical nose cap 13 carried by he front end of the section 11 and closing the adjacent ront end of the primary combustion chamber 12 to the ttmosphere. Also, the engine 10 comprises an elongated ongitudinally extending and rearwardly converging tubuar section 14 defining therein a secondary combustion :hamber 15. The section 14 is of frusto-conical configuraion; and the rear end of the section 11 is connected to :he front end of the section 14, with the rear end of :he primary combustion chamber 12 opening into the front end of the secondary combustion chamber 15. Also,

:he engine 10 comprises an elongated longitudinally ex- ;ending tubular section 16 defining an exhaust passage 17 therethrough. The section 16 is substantially cylindrical; and the rear end of the section 14 is connected to the front end of the section 16, with the rear end of the secondary combustion 15 opening into the front end of the exhaust passage 17. Also, the engine 10 comprises an elongated longitudinally extending and rearwardly diverging tubular section 18 defining an exhaust passage 19 therethrough. The section 18 is of frusto-conical configuration; and the rear end of the section 16 is connected to the front end of the section 18, with the rear end of the exhaust passage 17 opening into the front end of the exhaust passage 19. The rear end of the section 18 is open, whereby the rear end of the exhaust passage 19 constitutes an exhaust gas nozzle communicating with the atmosphere. In the arrangement, the center of the cap 13 and the longitudinal center lines of the sections 11, 14, 16 and 18 are arranged along a common longitudinal center line. Thus: the section 11 is disposed immediately rearwardly of the forwardly directed conical nose cap 13; the section 14 is disposed immediately rearwardly of the section 11; the section 16 is disposed immediately rearwardly of the section 14; and the section 18 is disposed immediately rearwardly of the section 16.

Further, the engine 10 comprises a plurality of elongated longitudinally extending and rearwardly directed tubular sections 20 respectively defining a corresponding plurality of inlet passages 21 therethrough; which sections 20 are arranged in an assembly disposed about the section 14 and projecting rearwardly about the section 16. As illustrated, four of the sections 20 are provided; which four sections 20 are arranged in substantially equal angularly spaced-apart relation. Each of the sections 20 comprises front and rear portions, respectively indicated at 20A and 20B. The front portion 20A of each section 20 projects radially outwardly and rearwardly from the common longitudinal center line of the sections 11, 14, 16 and 18; while the rear portion 20B of each section 20 is disposed in lateral off-set relation with the common longitudinal center-line mentioned and substantially parallel thereto. The extreme front end of the front portion 20A of each section 20 is connected to the front portion of the section 14 and rearwardly of the section 11 and with the adjacent front portion of the corresponding inlet passage 21 opening into the front portion of the secondary combustion chamber 15 through a corresponding adjacent hole 22 formed in the wall of the section 14. The rear end of each section 20 is open, whereby the adjacent rear end of the corresponding inlet passage constitutes an air inlet nozzle communicating with the atmosphere. The extreme rear end of the rear portion 20B of each section 20 is outwardly and forwardly rolled to provide a reinforcing cuff 23 surrounding the adjacent air inlet nozzle.

Further, the engine 10 comprises a plurality of fuel injectors 24 respectively arranged within the front ends of the inlet passages 21 and within the adjacent front portion of the secondary combustion chamber 15. Each one of the fuel injectors 24 is oriented along the axis of the front portion 20A of the corresponding one of the sections 21) and is directed inwardly toward the rear portion of the primary combustion chamber 12 and substantially at the longitudinal center line of the section 11. The fuel injectors 24 are respectively supported by the respectively adjacent front portions 20A of the sections 20; and the fuel injectors 24 are commonly connected to a fuel tank not shown; which fuel tank may contain any suitable liquid fuel, such as gasoline, etc. Further, the engine 10 comprises an ignition device 25, that may be in the form of a spark plug; which ignition device 25 may be arranged in a fixture, not shown, carried by the wall of the section 11 adjacent to the nose cap 13, and projecting into the front portion of the primary combustion chamber 12. The ignition device 25 is connected to a spark coil, or the like, for the usual spark purpose.

In the construction of the engine 10, the elements 11,

13, 14, 16 and 18 are formed of sheet metal such as a suitable stainless steel. In a constructional example, the stainless steel mentioned was of the Fe-Cr-Ni type, having a thickness of 1 mm. This engine 10 had a total weight of only 37 pounds, and developed a forward thrust of approximately 250 pounds, when burning ordinary gasoline. The section 11 had an inside diameter of 240 mm. and a length of 480 mm.; and the nose cap 13 had a length of mm. The section 16 had an inside diameter of 120 mm.; and the section 14 had an inside diameter at the front end thereof of 240 mm. and an inside diameter at the rear end thereof of 120 mm. The section 14 had a length of 240 mm.; and the section 16 had a length of 120 mm. The section 18 had an inside diameter at the front end thereof of 120 mm. and an inside diameter at the rear end thereof of 240 mm.; and the section 18 had a length of 1810 mm. Each of the sections 20 had an inside diameter of mm.; the center line of each front portion 20A was disposed at an angle of 37 /2 to the common longitudinal center line of the sections 11, 14, 16 and 18; and the longitudinal center lines of oppositely disposed ones of the rear portions 203 were laterally spaced-apart by 330 mm. The rear portion 203 of each section 20 had a length of 375 mm. along the longitudinal center line thereof.

Considering now the general mode of operation of the engine 10, and assuming starting thereof, and also assuming that there is a combustible or explosive mixture of fuel and air in the primary combustion chamber 12, the ignition device 25 is fired to cause an explosion of the mixture in the primary combustion chamber 12, whereby the explosion of the mixture proceeds rearwardly therethrough and then rearwardly through the secondary combustion chamber 15. The hot burning gases then proceed rearwardly through the tandem related exhaust passages 17 and 19 and thence through the exhaust gas nozzle at the extreme rear end of the exhaust passage 19 to the atomosphere. Of course, the rearward discharge of the gases through the exhaust gas nozzle provides a forward thrust of the engine 10 in a known manner. Some of the burning gases in the secondary combustion chamber 15 rush through the openings 22 and rearwardly through the inlet passages 21 and thence through the air inlet nozzles at the extreme rear ends of the inlet passages 21, so as to produce additional forward thrust of the engine however, the amount of burning gases that rush through any one of the holes 22 into the associated inlet passage 21 is not substantial by virtue of the abrupt off-set of the front portion 20A of the associated section 20 with respect to the common longitudinal center line of the sections 11, 14, 16 and 18. Moreover, the total length of each section 20 is substantially less than the combined lengths of the sections 14, 16 and 18. Accordingly, the mass of rearwardly moving burning gases causes a piston effect in the secondary combustion chamber and the connected exhaust passages 17 and 19; whereby a partial vacuum is shown in the secondary combustion chamber 15 and in the connected inlet passages 21 prior to the complete exhausting of the hot burning gases from the exhaust gas nozzle at the extreme rear end of the exhaust passage 19.

Thus, as the forward thrust subsides, the partial vacuum developed in the secondary combustion chamber 15 causes fresh air to rush into the air intake nozzles at the extreme rear ends of the intake passages 21; whereby plural streams of fresh air proceed forwardly through the intake passages 21 and are projected over the fuel injectors 24 and then directed forwardly with great turbulence into the rear of the primary combustion chamber 12 in which the-re is small residual burning gases. As the streams of fresh air proceed over the fuel injectors 24, the fuel injectors 24 are operated; whereby fuel is injected into the streams of fresh air, so as to produce explosive mixtures or streams of gases directed into the rear of the primary combustion chamber 12. Thus, the new mixture of gases is exploded to produce another forward thrust of the engine 10.

In view of the foregoing, it will be understood that the explosions are intermittent, and that after ignition or starting of the engine 10, the ignition device 25 is cutoff, since automatic intermittent operation or pulsing of the engine 10 is assured by the normal mode of operation thereof. In order to arrest intermittent operation of the engine 10 it is only necessary to cut-01f the supply of fuel to the injectors 24, in an obvious manner.

Reconsidering the constructional example above described, it is noted that the engine 10 had an operating frequency of approximately 80 cycles per second, as established by the dimensions of the fundamental elements 11, 14, 16, 18 and thereof. In this construction, the sum of the areas .of the transverse cross-sections of the inlet passages 21 measured at their points of connection to the element 14 is between 40% and 55% of the area of the largest transverse cross-section of the primary combustion chamber 12; and the sum of the areas of the inlet passage 21 may attain as much as 66% of the largest transverse cross-sectional area of the primary combustion chamber 12. The best operation of the engine 10 is obtained when the sections 20 have a length between 70% and 100% of the length of the primary combustion chamber 12.

Referring now to FIG. 2, the modified form of the pulse-jet engine 110 there illustrated is substantially identical to the pulse-jet engine 10 and thus comprises the identical elements 111, 112, 114, 115, 116 and 117 as indicated. Also, in this case, the engine 110 comprises a plurality of individual tubular parts 120A, 120B, 120C and 120D arranged in tandem relation from the front end to the rear end of the section 120. Specifically, the tubular part 120A is substantially cylindrical and is connected at the extreme front end thereof to the wall of the section 114 so that the extreme front end of the inlet passage 121 communicates with the secondary combustion chamber 115 for the purpose previously explained. The tubular part 120B is substantially cylindrical and is connected at the front end to the rear end of the part 120A.

6 The tubular part 120C diverges rearwardly and is thus of frusto-conical configuration, the extreme front end of the part 120C being connected to the rear end of the part 120B. The tubular part 120D is substantially cylindrical and is connected at the extreme front end thereof to the rear end of the part 1200. Also, the extreme rear end of the inlet passage 121 defines in the part 120D an air inlet nozzle communicating with the atmosphere; and the extreme rear end of the part 120D is provided with a reinforcing cuff 123 surrounding the air inlet nozzle mentioned.

The general mode of operation of the engine is essentially the same as that of engine 10 and this description is not repeated in the interest of brevity.

Referring now to FIG. 3, another modified form of the pulse-jet engine 210 as there illustrated that is of the fundamental construction and arrangement of the engine 10; whereby the engine 210 comprises the identical elements 211, 212, 213, 214, 215, 216, 217, 218, 219, 220 and 221. Also, the engine 210 comprises a plurality of elongated longitudinally extending sections 230 respectively defining a plurality of passages 231 therethrough. The sections 230 are arranged in an assembly about the sections 216 and 218 and are supported jointly thereby. Also, the sections 230 are respectively operatively associated with the sections 220; whereby the longitudinal center lines of the sections 230 are substantially respectively aligned with the center lines of the sections 220. Each of the sections 230 diverges rearwardly, whereby each of the sections 230 constitutes an aspirator providing the aspirating passage 231 therethrough.

In the engine 210, the extreme rear end of each of the sections 220 is reinforced by an associated surrounding cuff 223. Similarly, the extreme front end of each of the aspirators 230 is reinforced by an associated surrounding culf 232.

The general mode of operation of the engine 210 is essentially the same as that of the engine 10; however, the aspirators 230 are useful in conjunction with the amplification of the thrust of the hot burning gases that are ejected through the air inlet nozzles provided in the extreme rear ends of the sections 220. Specifically, as a mass of burning gases is ejected from one of the air inlet nozzles provided in the rear end of a corresponding one of the sections 220, the same is directed into the front end of the associated one of the aspirators 230 causing a large volume of air to be drawn therewith into the adjacent front end of the aspirating passage 231 through the associated one of the aspirators 230. The hot burning gases heat the airthat is thus drawn into the front end of the aspirator 230, whereby the mass of the gases in the aspirating passage 231 is expanded causing a corresponding forward thrust to be exerted upon the wall of the aspirator 230. Accordingly, the aspirators 230 assist with the production of the total forward thrust of the engine 210 in the operation thereof.

Referring now to FIGS. 4 to 7, inclusive, a further modified form of a portion of the pulse-jet engine 310 is there illustrated that may be identical to the engine 10, except that one or more of the sections 320 is provided with an air intake scoop 350. Specifically, the air scoop 350 illustrated is carried by the extreme rear end of the section 320 adjacent to the air inlet nozzle formed at the extreme rear end of the air inlet passage 321 extending through the section 320, the extreme rear end of the section 320 being provided with a surrounding reinforcing cuff 323 for the purpose previously explained.

Specifically, the air scoop 350 is of elongated longitudinally extending tubular form and defines an air passage 351 therethrough. More particularly, the front end of the scoop 350 is open, whereby the adjacent front end of the air passage 351 communicates with the atmosphere. The rear portion of the air scoop 350 is return bent downwardly and thence forwardly, as indicated at 352, so that the extreme rear end of the air scoop 350 is also for- 'ardly directed, with the result that the extreme rear end f the passage 351 is directed forwardly interiorly of the ir inlet passage 321 extending through the section 320.

In the construction, the center line of the extreme rear rid of the scoop 350 extends downwardly and forwardly ato the extreme rear end of the air inlet passage 321; and pecifically, the open front end of the passage 351 and the ear end of the passage 351 are both forwardly directed, s best illustrated in FIG. 6.

In the arrangement, the air scoop 350 may be suitably ecured to the rear end of the section 320 and in emracing relation With respect to the associated reinforcing 111T 323.

The general mode of operation of the engine 310 is :ssentially the same as that of the engine 10, except in this :ase forward movement of the engine 310 causes fresh ill to be caught in the open front end of the air scoop 550; whereby the air flows rearwardly in a stream through he passage 351, and is ultimately projected through the )pen rear end of the air scoop 350 and forwardly into :he adjacent rear end of the air inlet passage 321 extending :hrough the associated section 320.

The arrangement of the air scoop 350 upon at least one of the sections 320 facilitates starting of operation of the pulse-jet engine 310 in an obvious manner, assuming that the engine 310 is moving forwardly as a part of an airplane, or other forwardly moving vehicle.

As this point, it is noted in conjunction with the pulsejet engines 10, 110 and 210 that auxiliary starting facility must be provided to initiate operation thereof. This auxiliary starting equipment may comprise one or more of the air scoops 350 as described in conjunction with pulse-jet engine 310.

On the other hand, the auxiliary starting equipment may be of any suitable form such, for example, as a cylinder of compressed air and a valve connection therefrom via one of the sections 20, 120 or 220, so as to accommodate the initial introduction into the primary combustion chamber 12, 112 or 212 of an explosive or combustible mixture of fuel and air. In other words, in the arrangements of the puse jet engines 10, 110', 210 and 310 only the engine 310 is self-starting by virtue of the provision of the air scoop 350' carried by the associated section 320.

Pulse-jet engines of the character of those herein disclosed are particularly suitable for incorporation into an airplane, as an auxiliary engine, as disclosed in US. Patent No. 3,134,561, granted on May 26, 1964, to Deodat Clejan. Specifically, this airplane comprises a main engine of the piston type operatively connected to a propeller and at least one auxiliary engine of the pulse-jet type, together with an arrangement for placing the auxiliary engine into operation in the event of failure of the main engine.

In view of the foregoing, it is apparent that there has been provided a pulse-jet engine of improved and simplified construction and arrangement that is exceedingly compact and lightweight with respect to the forward thrust delivered thereby, and relative to conventional such engines, whereby the improved engine is ideally suited as an auxiliary engine in an airplane that is normally operated by a propeller driven by a conventional engine of the piston type.

While there has been described what is at present considered to be the preferred embodiment of the invention, it will be understood that various modifications may be made therein, and it is intended to cover in the appended claims all such modifications as fall within the true spirit and scope of the invention.

What is claimed is:

1. A valveless pulse-jet engine comprising an elongated longitudinally extending tubular first section defining therein a primary combustion chamber, a cap connected to the front end of said first section and closing the adjacent front end of said primary combustion chamber to the atmosphere, an elongated longitudinally extending and rearwardly converging tubular second section defining therein a secondary combustion chamber, the rear end of said first section being connected to the front end of said second section with the rear end of said primary combustion chamber opening into the adjacent front end of said secondary combustion chamber, an elongated longitudinally extending tubular third section defining an exhaust passage therethrough, the rear end of said second section being connected to the front end of said third section with the rear end of said secondary combustion chamber opening into the front end of said exhaust passage, the rear end of said third section being open, whereby the rear end of said exhaust passage constitutes an exhaust gas nozzle communicating with the atmosphere, the longitudinal axes of said first and second and third sections being arranged substantially in alignment along a com mon longitudinal axis, said second section having a length that is about /2 of that of said first section and that is about A; that of said third section, an elongated longitudinally extending tubular fourth section defining an inlet passage therethrough, the longitudinal axis of said fourth section being in lateral off-set relation with respect to said common axis, the front end of said fourth section being connected to the front portion of said second section with the adjacent front end of said inlet passage opening into the front portion of said secondary combustion chamber, the rear end of said fourth section being open, whereby the adjacent rear end of said inlet passage constitutes a rear inlet nozzle communicating with the atmosphere, an elongated longitudinally extending tubular fifth section defining a scoop passage therethrough, the longitudinal axis of said fifth section being disposed in lateral off-set relation with respect to the longitudinal axis of said fourth section, the front end of said fifth section being open, whereby the adjacent front end of said scoop passage constitutes a mouth communicating with the atmosphere, the rear portion of said fifth section having a return bend therein disposed adjacent to the rear end of said fourth section, the rear end of said fifth section being forwardly directed and disposed in said air inlet nozzle, the rear end of said fifth section being open, whereby the adjacent rear end of said scoop passage constitutes an air outlet nozzle communicating with said air inlet nozzle, means for injecting fuel in finely divided form forwardly through the front end of said secondary combustion chamber and into the rear end of said primary combustion chamber and directed toward the front end thereof, and means for igniting the combustible mixture of fuel and air in said primary combustion chamber.

2. The valveless pulse-jet engine set forth in claim 1, wherein the transverse cross-sectional area of said rear end of said fifth section is somewhat greater than the transverse cross-sectional area of said front end of said fifth section, and the transverse cross-sectional area of said rear outlet nozzle is substantially smaller than the transverse cross-sectional 'area of said rear inlet nozzle.

References Cited UNITED STATES PATENTS 2,574,460 11/1951 Bohanon 6039.77 2,731,795 1/1956 Bodine 60-249 2,795,105 6/1957 Porter 60249 2,998,705 9/ 1961 Porter et al 60-249 FOREIGN PATENTS 1,345,689 11/ 1963 France.

MARK M. NEWMAN, Primary Examiner.

CARLTON R. CROYLE,Examiner.

D. HART, Assistant Examiner. 

1. A VALVELESS PULSE-JET ENGINE COMPRISING AN ELONGATED LONGITUDINALLY EXTENDING TUBULAR FIRST SECTION DEFINING THEREIN A PRIMARY COMBUSTION CHAMBER, A CAP CONNECTED TO THE FRONT END OF SAID FIRST SECTION AND CLOSING THE ADJACENT FRONT END OF SAID PRIMARY COMBUSTION CHAMBER TO THE ATMOSPHERE, AND ELONGATED LONGITUDINALLY EXTENDING AND REARWARDLY CONVERGING TUBULAR SECOND SECTION DEFINING THEREIN A SECONDARY COMBUSTION CHAMBER, THE REAR END OF SAID FIRST SECTION BEING CONNECTED TO THE FRONT END OF SAID SECOND SECTION WITH THE REAR END OF SAID PRIMARY COMBUSTION CHAMBER OPENING INTO THE ADJACENT FRONT END OF SAID SECONDARY COMBUSTION CHAMBER, AN ELONGATED LOGITUDINALLY EXTENDING TUBULAR THIRD SECTION DEFINING AN EXHAUST PASSAGE THERETHROUGH, THE REAR END OF SAID SECOND SECTION BEING CONNECTED TO THE FRONT END OF SAID THIRD SECTION WITH THE REAR END OF SAID SECONDARY COMBUSTION CHAMBER OPENING INTO THE FRONT END OF SAID EXHAUST PASSAGE, THE REAR END OF SAID THIRD SECTION BEING OPEN, WHEREBY THE REAR END OF SAID EXHAUST PASSAGE CONSTITUTES AN EXHAUST GAS NOZZLE COMMUNICATING WITH THE ATMOSPHERE, THE LONGITUDINAL AXES OF SAID FIRST AND SECOND AND THIRD SECTIONS BEING ARRANGED SUBSTANTIALLY IN ALIGNMENT ALONG A COMMON LONGITUDINAL AXIS, SAID SECOND SECTION HAVING A LENGTH THAT IS ABOUT 1/2 OF THAT OF SAID FIRST SECTION AND THAT IS ABOUT 1/8 THAT OF SAID THIRD SECTION, AN ELONGATED LONGITUDINALLY EXTENDING TUBULAR FOURTH SECTION DEFINING AN INLET PASSAGE THERETHROUGH, THE LONGITUDINAL AXIS OF SAID FOURTH SECTION BEING IN LATERAL OFF-SET RELATION WITH RESPECT TO SAID COMMON AXIS, THE FRONT END OF SAID FOURTH SECTION BEING CONNECTED TO THE FRONT PORTION OF SAID SECOND SECTION WITH THE ADJACENT FRONT END OF SAID INLET PASSAGE OPENING INTO THE FRONT PORTION OF SAID SECONDARY COMBUSTION CHAMBER, THE REAR END OF SAID FOURTH SECTION BEING OPEN, WHEREBY THE ADJACENT REAR END OF SAID INLET PASSAGE CONSTITUTES A REAR INLET NOZZLE COMMUNICATING WITH THE ATMOSPHERE, AN ELONGATED LONGITUDINALLY EXTENDING TUBULAR FIFTH SECTION DEFINING A SCOOP PASSAGE THERETHROUGH, THE LONGITUDINAL AXIS OF SAID FIFTH SECTION BEING DISPOSED IN LATERAL OFF-SET RELATION WITH RESPECT TO THE LONGITUDINAL AXIS OF SLAID FOURTH SECTION, THE FRONT END OF SAID FIFTH SECTION BEING OPEN, WHEREBY THE ADJACENT FRONT END OF SAID SCOOP PASSAGE CONSTITUTES A MOUTH COMMUNICATING WITH THE ATMOSPHERE, THE REAR PORTION OF SAID FIFTH SECTION HAVING A RETURN BEND THEREIN DISPOSED ADJACENT TO THE REAR END OF SAID FOURTH SECTION, THE REAR END OF SAID FIFTH SECTION BEING FORWARDLY DIRECTED AND DISPOSED IN SAID AIR INLET NOZZLE, THE REAR END OF SAID FITH SECTION BEING OPEN, WHEREBY THE ADJACENT REAR END OF SAID SCOOP PASSAGE CONSTITUTES AN AIR OUTLET NOZZLE COMMUNICATING WITH SAID AIR INLET NOZZLE, MEANS FOR INJECTING FUEL IN FINELY DIVIDED FORM FORWARDLY THROUGH THE FRONT END OF SAID SECONDARY COMBUSTION CHAMBER AND INTO THE REAR END OF SAID PRIMARY COMBUSTION CHAMBER AND DIRECTED TOWARD THE FRONT END THEREOF, AND MEANS FOR IGNITING THE COMBUSTIBLE MIXTURE OF FUEL AND AIR IN SAID PRIMARY COMBUSTION CHAMBER. 